Native Modules

Electrode Native supports some popular native modules such as react-native-vector-icons, react-native-code-push or react-native-maps for example. And the React Native open source community provides many additional native modules that could be used in your MiniApps.

If the Electrode Native version you are using does not yet support a native module that you would like to use, you can add support for it to Electrode Native by creating a plugin configuration in the manifest--this would be your override manifest in the case of a private native module or the master manifest for an open source native module.

Why does Electrode Native require a plugin configuration? In a pure React Native mobile application, you can use the react-native link command (formerly the rnpm command) to add a React Native plugin (native module) to your React Native application. However, Electrode Native requires that you add the native modules to a container library--not directly to a mobile application.

Note Electrode Native generated APIs and API implementations have a specific structure and additional configuration is not needed to support them in Electrode Native. However, if you plan to work on a new native module, it's recommended that you consider using Electrode Native APIs.

Creating plugin configurations

In the manifest repository, the supported plugin configurations are located in the plugins directory. This plugins directory contains sub-directories that follow a specific naming convention that is used by Electrode Native to correctly match a plugin version with a plugin configuration--for a specific Electrode Native version.

The list below shows an example of the directory naming convention that matches Electrode Native versions.

plugins/ern_v0.2.0+
plugins/ern_v0.4.0+

Considering the example above, if you are using version ern 0.3.0, the Electrode Native platform looks for a matching plugin configuration in the plugins/ern_v0.2.0+ directory. If you are using version ern 0.5.0, the Electrode Native platform looks for a matching plugin configuration first in the plugins/ern_v0.4.0+ directory and if the configuration is not found that directory, the platform looks in the plugins/ern_v0.2.0+ directory.

In addition, the plugin configuration files are located in directories within the version directories. These directories also follow a naming convention used by the Electrode Native platform to lookup a plugin configuration, for example:

plugins/ern_v0.2.0+/react-native-code-push_v1.17.0+
plugins/ern_v0.2.0+/react-native-linear-gradient_v2.0.0+
plugins/ern_v0.2.0+/react-native-maps_v0.13.1+
plugins/ern_v0.2.0+/react-native-maps_v0.14.0+
plugins/ern_v0.2.0+/@myscope/react-native-my-module_v1.0.0+

The naming of these directories includes the minimum version of the plugin that the configuration targets. If a newer version needs a different configuration, a new directory can be created. This is shown in the above example for the react-native-maps.

The plugin configuration file is located within these sub-directories.

Configuration example

The following example shows the configuration files for the react-native-code-push plugin. The directory is located here

CodePushPlugin.java
ElectrodeCodePushConfig.h
ElectrodeCodePushConfig.m
config.json

Although the plugin has support for both iOS and Android platforms. Your native module can support only one platform.

The CodePushPlugin.java file contains configuration information to add the CodePush native module package to the list of native modules--to be loaded by React Native upon initialization of the Android Container library. The file can optionally include the configuration to allow the mobile app to configure the native module.

The ElectrodeCodePushConfig.h file and ElectrodeCodePushConfig.m file contains similar code for the iOS platform.

The config.json file holds the actual plugin configuration. It contains instructions that the container generator will use to add the plugin to the container.

The document can contain one or two top-level objects: android and/or ios. If a plugin is only supported on one platform, it will only contain that specific platform object.

There are two supported injection configuration directives:

• The platform agnostic directives can be used for both iOS and Android platforms.

• The platform specific directives can be used only in the context of a specific platform.

Platform-agnostic directives

The platform-agnostic directives are described in this section.

• copy

Used to copy one or more files or directories to the target container directory. The copy directive is an array of objects, each containing a specific copy statement. The objects contain a source property and a dest property:

• source : A single file path or directory glob indicating the files to copy

• dest : A target directory where the files will be copied to

Example

"copy":[
   {
      "source":"ios/**",
      "dest":"{{{projectName}}}/Libraries/CodePush"
   }
]

The example above shows how to copy the entire content (files and directories) of the plugin ios directory to the container /Libraries/CodePush directory.

All plugin code needs to be injected in the container--therefore they will have at least one copy statement in the config.json file. For the most part, in iOS, the dest will be "{{{projectName}}}/Libraries/{PLUGIN_NAME}". projectName will be replaced during Container generation by the name of the project (ElectrodeContainer in the case of container generation), while PLUGIN_NAME should be the name of the plugin itself.

• replaceInFile

Used to perform string replacements in specified files. This is useful for the iOS platform as some plugins are sometimes needed to replace the way imports are performed. The replaceInFile directive is an array of objects, each containing a specific replacement statement. The objects contain a path property, a string property and a replaceWith property:

• path : Path to the file that contains a string to be replaced

• string : String to be replaced

• replaceWith : The new string

Example

{
  "path": "{{{projectName}}}/Libraries/RNLocation/RNLocation.h",
  "string": "\"RCTBridgeModule.h\"",
  "replaceWith": "<React/RCTBridgeModule.h>"
}

This example shows how to replace the string "RCTBridgeModule.h" with <React/RCTBridgeModule.h> in the /Libraries/RNLocation/RNLocation.h file in the container.

• applyPatch

Apply a given patch file, by running git apply command, from a specific directory. The value of this property should be a single object containing the following two properties :

• patch : Path to the patch file to apply, relative to the directory containing the pluging configuration file (config.json).

• root : Path to the directory from which to run the git apply command, relative to the container generator output directory. Mutually exclusive with inNodeModules.

• inNodeModules : If true, root will be set to root location of the plugin in node nodules. Mutually exclusive with root.

Example

{
  "patch": "example.patch",
  "root": "{{{projectName}}}/Libraries/ExampleNativeModule"
}

This example applies the example.patch patch file, by running git apply command from the {{{projectName}}}/Libraries/ExampleNativeModule directory.

Platform-specific directives

The platform-specific directives for Android and iOS are described in this section.

Android

The following directives can only be used inside an android configuration object.

• moduleName

The name of the Android module containing the plugin. By default, the plugin configuration uses lib, which is the convention most Android plugins adopt to name the module containing the plugin code.

• root

The root directory containing the Android module. By default, the plugin configuration uses android, which is the convention followed by most third-party native modules.

• dependencies

An array of one or more dependencies (in format "::") that the native module is dependent on. The container generator will add all of these extra dependencies as implementation statements in the container build.gradle file.

For special dependency statements needs, not using default implementation <groupId>:<artifactId>:<version> format, it is possible to set the full dependency statement to be injected in the build.gradle as illustrated in the following example:

For example

"dependencies": [
  "com.google.android.gms:play-services-base:10.0.1",
  "implementation('com.crashlytics.sdk.android:crashlytics:2.9.2@aar') { transitive = true }",
  "implementation platform('com.foo:bar-pom:1.0.0')"
]

Will result in the following injection in build.gradle:

implementation 'com.google.android.gms:play-services-base:10.0.1'
implementation('com.crashlytics.sdk.android:crashlytics:2.9.2@aar') { transitive = true }
implementation platform('com.foo:bar-pom:1.0.0')

• features

An array of one or more Android hardware or software features used by the native module, to add to the container manifest when injecting this plugin.

For example

"features" : [
  "android.hardware.bluetooth"
]

Will result in the following injection in Container manifest

<uses-feature android:name="android.hardware.bluetooth" />

• Android Resources

If the native module is containing android resources (typically in src/main/res) you can use the copy directive to copy the resources directories to the container. For example, assuming the android resources directory is located in android/src/main/res (relative to the root of the native module package), and the package name of the native module is react-native-example, then you should add the following directive to properly copy the native modules resources to the container :

"copy": [
  {
    "source": "android/src/main/res/*",
    "dest": "lib/src/main/res/react-native-example"
  }
]

Also, because resources are accessed via the R generated class, you'll have to make sure to update all imports of this class in the source files importing this class, to use the container namespace rather than the native module one. You can do so using replaceInFile directive, as illustrated:

"replaceInFile": [
  {
    "path": "lib/src/main/java/com/example/SourceFile.java",
    "string": "com.example.R",
    "replaceWith": "com.walmartlabs.ern.container.R"
  }
]

iOS

The following directives can only be used inside an ios configuration object.

• containerPublicHeader

Specifies one or more header to surface in the Container umbrella header. This is used only for specific headers that must be accessed from outside the container by the application itself.

Example

"containerPublicHeader": [
  "ElectrodeBridgeHolder.h"
]

iOS also provides an additional directive object: pbxProj. The pbxProj directive can include directives used to manipulate the container .pbxproj file.

• addProject

Adds a plugin xcodeproj and its target library to the Container. - path : Path to the xcodeproj of the plugin

• group : Group to add the project to (Libraries should be used)

• staticLibs : An array of static libraries, targets of the plugin project, to link with the Container

Example

"addProject": [
  {
    "path": "AirMaps/AirMaps.xcodeproj",
    "group": "Libraries",
    "staticLibs": [
      {
        "name":"libAIRMaps.a",
        "target":"AirMaps"
      }
    ]
  }
]

• addHeaderSearchPath

Adds a header search path to the container. This directive is used to add the proper path to the plugin headers. This is an array of strings--each string is a specific path.

"addHeaderSearchPath": [
  "\"$(SRCROOT)/{{{projectName}}}/Libraries/AirMaps/**\""
]

• addHeader

Adds a header from the plugin project to the container headers.

• path : Path to the header file to add

• group : Group containing the header - public : Boolean indicated whether the header should be public or not (default to false)

{
  "path": "ElectrodeReactNativeBridge/ElectrodeBridgeEvent.h",
  "group": "ElectrodeReactNativeBridge",
  "public": true
}

• addSource

Adds a source file from the plugin project to the container list of sources.

• path : Path to the source file to add - group : Group containing the source file

{
  "path": "ElectrodeReactNativeBridge/ElectrodeObject.swift",
  "group": "ElectrodeReactNativeBridge"
}

• setBuildSettings

Set one or more build setting(s) in one or more pbxproj(s) associated to the plugin. For example setting ENABLE_BITCODE to NO for Debug and Release configurations of Example plugin project :

"setBuildSettings": [
  {
    "path": "{{{projectName}}}/Libraries/Example/Example.xcodeproj/project.pbxproj",
    "buildSettings": {
      "configurations": ["Debug", "Release"],
      "settings": { "ENABLE_BITCODE": "NO" }
    }
  }
]

• iOS Resources

If the native module is containing resources that needs to be added to the container xcode project, you can use the copy directive to copy the resources to the container. For example, assuming the following ios/example/resources directory structure (relative to the root of the native module package)

ios/example/resources
├── Localizable.strings
├── Login.storyboard
└── Media.xcassets

You can add them all to the container, using the copy directive as illustrated below

"copy": [
  {
    "source": "ios/example/resources/*",
    "dest": "{{{projectName}}}/Resources"
  }
]

The dest should always be set to {{{projectName}}}/Resources. During container generation, ern will add any resources present in this directory, to the container xcode project.

The following directives are only available when using React Native >= 0.61.0

• podFile

Path to a Podfile to use for the Container, relative to the directory containing the plugin config.json file. Can only be set in 'react-native' plugin configuration.

• podspec

Path to a podspec file to use for the plugin, relative to the directory containing the plugin config.json file. Can be used in case a native module doesn't have yet an available podspec file or if the podspec file of the native module needs to be different than the one shipped with it.

• extraPods

Array of extra pod statements that will be injected in the Container Podfile.

• requiresManualLinking

Boolean flag that indicates whether this plugin requires manual linking. If defined and set to true, all plugin directives will be processed. If not defined (default) or set to false, only podFile, podspec and extraPods directives will be processed.\n This should only be set to true in very rare cases, for plugins that do not support auto linking.